Gas turbines with can combustors are known from various applications in power plants. Different gas turbines with can-annular combustor arrangements are known. Typically a plurality of combustors is disposed in an annular array about the axis of the turbine. Hot combustion gases flow from each combustor through a respective transition piece into the first stage vane. In addition to relative movement, e.g. due to dynamic pulsing between these components, the transition pieces and first stage vane are made of different materials and are subjected to different temperatures during operation, thereby experiencing different degrees of thermal growth. To allow such a “mismatch” at the interface of the transition pieces and the first stage vane support frames which support and guide the transition piece at the turbine inlet have been proposed. To allow movement between the transition piece and the support frames the US 2009/0115141 A1 suggests the use of sealed slots. It teaches the use of a remaining leakage to cool the transition piece and support frame.
However, the leakage can change during operation and cannot be guided to effectively cool all regions of the support frame. Thus, an effective sealing cannot be applied and large amounts of cooling gas can be lost in such an arrangement. In addition, the vanes of the first stage of a gas turbine are directly exposed to the hot combustion gases, and they also require a significant amount of cooling gas.
What is needed is an arrangement that can provide benefits of having an effective transition region between the combustor and the turbine, but at same time this arrangement should have reduced cooling needs compared to known solutions.